1. Field of Invention
The present invention relates to a method for forming a semiconductor device. More particularly, the present invention relates to a method for forming a color filter.
2. Description of Related Art
Recently, various displays comprising Liquid Crystal Display (LCD), Field Emission Display (FED), Organic Light Emitting Diode (OLED), and Plasma Display Panel (PDP) have come to be widely used in daily life, such as those applied in TVs, computers, projectors, mobile phones, and personal audio-visual fittings.
The difference among different types of displays lies in the imaging manner. One of them utilizes a light source, several optical elements composed of prism groups, and multiple panels corresponding to each beam. The principle thereof is that the light source (white light) is filtered into three primary color beams, R, G, B, with the prism groups, and then modulated with three panels to make the image signals carried in the three beams. Finally; the images can be synthesized by optical elements, such as, dichroic prisms and lenses. However, the three panels comprise a micro-display.
The micro-display can be applied in various kinds of displays, such as, LCD or OLED. However, besides the display region for forming the color filter thereon, the substrate further comprises the peripheral region having trenches serving as die seal ring or openings for exposing the metal pad underneath. Hence, during the different color filter layers are formed over the substrate to form the color filter array, the step high of the trench would lead to the striation effect of the color filter layers. The striation of the color filter layers extends from the trenches within the peripheral region of the substrate into the display region of the substrate. Therefore, the display performance is degraded.